--- In
Homebrew_PCBs@yahoogroups.com, Stefan Trethan
<stefan_trethan@...> wrote:
>
> But one mil copper would be like 25um thick, as far as i know only
> 18um and 35um is available easily?
> (It is called 1oz and 1/2oz of copper weight per some specific area
in the US.)
>
∗Laughing∗ - you know Stefan, we tried to go metric back in the 70's,
it just wouldn't take here. Dare to be different I guess. Funny how
we won't move from a systems that you fellows invented and abandoned
isn't it? Oh well, personally, I admit I do like the English system of
measurement better.
Anyways, the copper thickness is in oz per square foot. One in^3 of
copper has a mass of 5.179oz, so 1oz of copper has a volume of .1931
in^3. Divide this by 144 (12x12) to spread it out over an area of 1
ft² and you get a thickness of 1.3 mils (0.0013") ... half that for
1/2oz copper. Easy no? (No!)
Phil